Design of high-performance ion-pairing luminescent dyes via donor group and alkyl chain engineering for agricultural light-converting films

Agricultural films have attracted considerable attention in recent years. Herein, four types of organic-inorganic complex red light conversion agents (W-2L, W-8L, S-8L, H-8L) were designed, the S-8L conversion agent exhibits an extremely broad ultraviolet absorption range of 200-400 nm. Contact angle (142.7°) tests confirmed its excellent hydrophobic properties, enabling better compatibility with LLDPE substrates. Meanwhile, its outstanding photothermal stability of S-8L was demonstrated by a long red fluorescence lifetime: 478.14 μs, an exceptional fluorescence quantum yield: 76.77 %, a high initial decomposition temperature and an extended ultraviolet aging resistance period. Furthermore, the S-8L1 conversion film was utilized to assist in the cultivation of Chlorella cells, demonstrating its excellent UV-blocking and red-light conversion capabilities, significantly increasing both biomass and chlorophyll content. This work proposed a potential way to develop highly efficient light conversion agents by regulating the inorganic-organic functional groups.